DEVELOPMENT THEORIES. 329 



aerolites can traverse space, life germs cannot traverse 

 space likewise ? 



The unity of life throughout even the solar system 

 may be no more than a speculative guess, but something 

 not far short of authoritative unanimity in the scientific 

 world supports Professor Huxley in maintaining the 

 unity of succession in the vital organisms of our planet, 

 against the theory of an indefinite number of creations, 

 each preceded by a cataclysm destructive of all the life 

 upon earth. There is no paradox, however, in the 

 assertion that, at the time Miller wrote, and with the 

 facts Miller possessed, the genuine service which it was 

 his part to render to science implied and required that 

 he should controvert the popular theories of develop- 

 ment. To refuse to believe on insufficient evidence, 

 to point out in what respect the evidence is insufficient, 

 this is the most effective preparation that can be made 

 for the discovery of truth upon any subject. If philoso- 

 phers had been content, twenty-five years ago, to accept 

 as conclusively established the theories of Lamarck, 

 Demaillet, and the * Vestiges/ those researches by which 

 more light has been thrown upon the history of living 

 things in our planet than had been cast in ten pre- 

 ceding centuries, might never have been undertaken. 

 The highest service that can be rendered to science is 

 the discovery of new truth ; the next highest is the ex- 

 posure of false pretensions to the discovery of new truth. 

 In pointing out the unsoundness of the development 

 theories in vogue in his day, Miller was in the same line 

 of battle with his ablest scientific contemporaries. How 

 he would have comported himself if he had lived to see 

 the publication of Mr Darwin's work on the Origin 

 of Species, to witness its reception throughout the 

 world of science, to follow the lines of research and 



